The Gene Targeting and Transgenics Resource represents a new addition to this CCSG renewal application. Technical expertise currently exists at Roswell Park Cancer Institute Corporation (RPCI) to prepare mice with targeted mutations and transgenes in the laboratories of Drs. Paul Soloway and Kenneth Gross, respectively. These labs have enjoyed considerable success at generating novel strains of mice for their own research program sand for collaborators at RPCI. It is proposed that the genetic tools used in these two labs should be folded into a core Resource to make them more available to investigators at RPCI. The reason for doing this is simple-demand for access to these technologies has outstripped the abilities of Drs. Soloway and Gross to provide them through their own laboratory research programs. This increased demand at RPCI parallels the need recognized by the national and international genetics community at large to develop new animal models for human disease. This goal has been enthusiastically supported by the NCI in the form of a program announcement encouraging the development of new animal models for cancer, which will inevitably involve the use of genetic technologies. The establishment of a core Resource dedicated to providing access to these technologies will enable RPCI investigators to compete effective for grants provided through these kinds of national programs. It is anticipated that each year this Resource will generate two mouse strains with targeted mutations and five strains with novel transgenes.